dagop: add smartset interface to filectxancestors()
The original filectx API is kept public since we'll need it to walk ancestor
(rev, match) pairs efficiently. The current implementation scans ancestors
twice for 'hg log -fp FILE'.
# See http://EditorConfig.org for the specification
root = true
[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true